According to popular online shopping websites, China has gone nuts over the tonic which sells for between $30-$150 for a bottle of 100 capsules.

In a great leap forward for the kangaroo meat industry, drought-stricken graziers hope the new trend will stiffen Chinese resolve to consume more of the Aussie icon. But Australian medical experts warn the drug, based on testosterone, is untested and without scientific data to support its claims of a super-sexed libido.

"The kangaroo is the symbol of Australia and highly reproductive,'' reads one label. "The male kangaroo may mate with 40 female kangaroos and produces twice as much semen as a bull. Essence of Kangaroo is extremely potent as it is rich in natural hormones, proteins, zinc and iron, which are able to increase physical strength and enhance the sexual energy.''

Roo ball expert John Kreuger, 73, of Townsville, a 40-year veteran of the testicle trade, this week meets with Chinese investors to buy his business "for the end product''.

He said the Chinese buyers wanted to dry the end product and turn it into a powder.

"We buy a tonne of testicles every month from roo meat processors and put them through my custom-made 'de-nutting' machine,'' Mr Kreuger said yesterday.

"It squeezes out the balls and leaves behind the empty pouch,'' he said. At his peak, he can process 500 hollowed scrota in an hour.

He then fashions the sack into bottle openers and sells them for $25 a pop.

Queensland Fertility Group medical director David Molloy said the virility drug was part of a male obsession with sexual performance.

"Doctors are very hesitant to endorse these products, as with so many therapies, there is no scientific data, no proper trials, certainly these drugs would never be registered,'' Dr Molloy said. "The hormone you'd mostly get from testicles is testosterone, in small quantities it may improve libido but in large doses it can cause loss of virility and fertility.

"This is not good news for kangaroos. But thank goodness it is not a product from an endangered species, like tiger penis, rhino horn, or other exotic animal species. Luckily there are plenty of red kangaroos out there.''

Essence of Kangaroo is a tonic capsule retailing for between 200 to 870 yuan ($34-$150) for a bottle of 100. A search on the popular taobao.com online shopping site threw up about 500 entries.